The authorities have identified a growing trend of children accessing inappropriate content on WLAN networks, especially using devices like mobile phones and tablets. WLAN Service Providers are being urged to implement adult content filtering in their network to protect children from inappropriate content. Moreover, mobile device manufacturers and mobile operators have been called upon to do more to advertise the threat of adult content access by children on WLAN networks and to provide parents with tools to protect their children from accessing inappropriate content. Currently, some cellular (mobile) network operators implement adult content filtering in their network. However, WLAN service providers generally do not offer adult content filtering capabilities today in their networks.
A mobile device user may have a subscription with a cellular (mobile) network operator or a primary WLAN service provider, and may specify their content filtering preferences with that cellular (mobile) network operator or primary WLAN service provider.
A cellular (mobile) network operator or primary WLAN service provider selling a WLAN subscription to a subscriber can provision the mobile device with a roaming list of allowed roaming partners to which that subscriber can roam. This means that the mobile device will use its SIM or USIM credentials to authenticate against those WLAN service providers. The subscription may contain a profile indicating whether content filtering is activated or not for this subscription.
One approach for the cellular (mobile) network operator or primary WLAN service provider to ensure that the user only accesses WLAN networks with adult content filtering in place is to define the roaming list to only include WLAN service providers that implement adult content filtering in their Wide Area Networks (WAN). One option is that adult content filtering support is negotiated as part of the contractual agreement between roaming partners. However, considering that the subscriber population requiring adult content filtering is assumed to be relatively small, it is likely that commercial decisions will be made not only on the basis of adult content filtering support. This means that there will be a possibility for users with subscriptions with adult content filtering restrictions to still gain access to a network with no adult content filtering in place. The only way the home cellular (mobile) network operator or primary WLAN service provider can prevent access to a roaming partner network is to build up a shortlist of networks with adult content filtering and restrict access to those networks for subscriptions where adult content filtering is active. Considering that the number of roaming partners of the operator can change in a relatively dynamic way and that a cellular (mobile) network operator or primary WLAN service provider can enter into international roaming relationships where the level of support for adult content filtering is more difficult to assess, it is a big burden for the home cellular (mobile) network operator or primary WLAN service provider to pick roaming partners for devices with subscriptions which have adult content filtering activated in their profile. This assessment can be relieved if a regulatory framework is in place that defines the criteria which must be satisfied for a local network to claim that it supports Adult Content Filtering. The provision of a restricted roaming partner list (only roaming partners supporting adult content filtering) is also not a secure mechanism as the user may always find means to modify the list and hence get access to network without adult content filtering. It is also important that customers with no adult content filtering in their subscriptions are able to access networks where adult content filtering is not in place if they want to avoid the irritation of content (sometimes even not actual adult content) from being blocked by an over restrictive adult content filtering engine.
One approach would be to implement content filtering on mobile devices. However, the effectiveness of the UE based filtering is limited by processing power on mobile devices, the reluctance of device manufacturers to support such functionalities on the device, the difficulty of maintaining up-to-date blacklists and adult content filtering policies on the device. It is also likely that the user will find a way to deactivate the content filtering on the device.